Plectropomus laevis

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA ACTINOPTERYGII PERCIFORMES EPINEPHELIDAE

Scientific Name: Plectropomus laevis
Species Authority: (Lacepède, 1801)
Common Name/s:
English Blacksaddled Coral Grouper
French Mérou Sellé
Spanish Mero Ensillado
Synonym/s:
Bodianus cyclostomus Lacepède, 1802
Bodianus cyclostomus Lacepede, 1802
Bodianus melanoleucos Lacepède, 1802
Bodianus melanoleucos Lacepède, 1802
Bodianus melanoleucus (Lacepède, 1802)
Bodianus melanoleucus (Lacepède, 1802)
Labrus laevis Lacepède, 1801
Labrus laevis Lacepède, 1801
Paracanthistius melanoleucus (Lacepède, 1802)
Paracanthistius melanoleucus (Lacepède, 1802)
Paracantistius maculatus (non Bloch, 1790)
Paracantistius maculatus (non Bloch, 1790)
Plectropoma maculatum (non Bloch, 1790)
Plectropoma maculatum Playfair, 1867
Plectropoma maculatum Playfair, 1867
Plectropoma maculatum (non Bloch, 1790)
Plectropoma maculatum Playfair, 1867
Plectropoma maculatum Playfair, 1867
Plectropoma melanoleucum (Lacepède, 1802)
Plectropoma melanoleucum (Lacepède, 1802)
Plectropomus laevis (Lacepède, 1801)
Plectropomus leopardus (non Lacepède, 1802)
Plectropomus leopardus (non Lacepède, 1802)
Plectropomus maculatum subspecies melanoleucum (Lacepède, 1802)
Plectropomus maculatus (non Bloch, 1790)
Plectropomus maculatus (non Bloch, 1790)
Plectropomus melanoleucus (Lacepède, 1802)
Plectropomus melanoleucus (Lacepède, 1802)
Taxonomic Notes: Often misidentified as Plectropomus maculatus (Heemstra and Randall 1993). In Australia small adults in blue spot phase misidentified as P. leopardus (CRC Reef Information Brochure).

Assessment Information [top]

Red List Category & Criteria: Vulnerable A2d+4d ver 3.1
Year Published: 2008
Date Assessed: 2008-01-01
Assessor/s: Choat, J.H., Liu, M., Craig, M.T., Yeeting, B. & Robinson, J.
Reviewer/s: Sadovy, Y. & Moss, K. (Grouper and Wrasse Red List Authority)
Justification:
Although this species is widespread, it is listed as Vulnerable (VU) because of its natural rarity, the heavy fishing pressure being experienced throughout its range, particularly the targeting of juveniles, and because it has shown declines in abundance of at least 30% (mature individuals). This trend is expected to continue into the future.

Geographic Range [top]

Range Description:General
Plectropomus laevis is widespread in the Indo-Pacific. Its range extends from the East African coast (Kenya to Mozambique) to the central and southern Pacific. Pacific latitudinal range from southern Japan to Middleton Elizabeth Reefs. Pacific longitudinal from the western Pacific to the Tuamotos and Pitcairn Island.

Specific
East Africa (Kenya to Mozambique), Comores, Madagascar, Tulear, Aldabara, Seychelles Réunion, Mauritius, Rodríguez, Chagos, Maldives, Lakshadweep, west India, Sri Lanka, Andamans, Nicobars, west Thailand, Myanmar, Sunda Shelf (excluding Malaya), Indonesia (excluding Irian Jaya), Bali, Sangalakki, Borneo, eastern Indonesia (excluding Aru), Flores, Komodo, Cocos-Keeling, Western Australia, Scott Reef, Rowley Shoals, Great Barrier Reef, Chesterfield Reefs, Coral Sea Reefs, Middelton Reef, Papua New Guinea, Vanuatu, New Caledonia, Loyalty Islands, Hong Kong, Taiwan, Peng Hu Shan, Ryukyu, Kashimo-Jima, Izu Islands, Ogashawara Islands, Korea (Ceju), Micronesia, Pohnpei, Marianas, Howland Island, Fiji, Tonga, Niue, Uvea, Samoa, Cook Island, Society Islands, Tuamotos, Gambier, Austral Islands, Pitcairn, and Rapa.

(Data from Robert Myers distributional database).
Countries:
Native:
American Samoa (American Samoa); Australia; British Indian Ocean Territory; Brunei Darussalam; China; Cocos (Keeling) Islands; Comoros; Cook Islands; Fiji; French Polynesia; Hong Kong; India; Indonesia; Japan; Kenya; Kiribati; Madagascar; Malaysia; Maldives; Marshall Islands; Mauritius; Mayotte; Micronesia, Federated States of ; Mozambique; Nauru; New Caledonia; Niue; Northern Mariana Islands; Palau; Papua New Guinea; Philippines; Pitcairn; Réunion; Samoa; Seychelles; Solomon Islands; Somalia; South Africa; Sri Lanka; Taiwan, Province of China; Tanzania, United Republic of; Tokelau; Tonga; Tuvalu; Vanuatu; Wallis and Futuna
FAO Marine Fishing Areas:
Native:
Indian Ocean – eastern; Indian Ocean – western; Pacific – northwest; Pacific – western central
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population: General
With the exception of Coral Sea reef localities Plectropomus laevis is invariably an uncommon to rare species achieving abundances of less than one individual per 1000 sq. m. Regional catch data indicates substantial declines.

The primary issue with P. laevis is the rarity of this large roving serranid over most of its range. Its congener P. leopardus was up to 10-15 times more abundant on the GBR in the 1980s (Ayling and Ayling 1986). In a series of surveys in 1994 to 2001, Ayling and Choat (unpublished) recorded abundances of ~0.3 individuals per 1000 sq. m in their main habitat in 1994, while similar surveys in 2001 recorded only 0.1-0.3 individuals per 1000 sq. m. In no-entry preservation zones the numbers remained at 0.3 individuals per 1000 sq. m. On remote far northern GBR and Coral Sea reefs and atolls, relatively high numbers (0.5-0.9 per 1000 sq. m) were recorded. However these numbers are not high when compared with a number of other exploited reef fish species. Increasing access to remote areas by charter line and spearfishers suggests numbers will continue to decline in the future. Relatively low numbers of P. laevis were recorded from offshore west Australian reefs both at fished sites (Ashmore Reef; Kospartov et al. 2006) and unfished sites (Rowley Shoals, Scott Reef; Done et al. 1994). This species was also found to be rare in the western Indian Ocean.

Fishery-dependent data
P. laevis is exploited over much of its range through line fisheries and is an important part of the live reef food fish trade (LRFFT). Catch records are difficult to interpret as a number of species may be aggregated under the term coral trout or leopard grouper.

As P. laevis (and especially the saddleback colour variant) is distinctive, a number of fishery databases exist that allow an analysis of trends. A review of the Maldives grouper fishery (Sattar and Adam 2005) identified the 8 most important grouper species in the line and diver-assisted fishery, which includes P. laevis-- one of the most valuable fishes in the live reef fish export trade (Table 3 in Sattar and Adam 2005).The fishery was initiated in 1994 with 1 million groupers being processed in 1997. By 2005, catch abundance had declined 75% with associated reductions in mean size. Additionally, fully 43% of the groupers taken at this time were immature. In response to declining abundance and mean size for targeted groupers, 16 species were protected under a quota system, with an annual quota of 30,000 individuals set for P. laevis. Twenty-one other serranid species did not receive quota protection.

Although no species-specific catch abundance estimates were included in Sattar and Adam (2005), a quantitative survey of the grouper fauna in the Maldives (Sluka 2001) revealed that P. laevis was rare, with abundance patterns similar to that obtained from the Seychelles.

A recent study in northern Indonesia (Scales et al. 2007) followed species-specific catch records for 6 species of grouper from 1995 to 2003. Total annual catch rate of the saddleback grouper (P. laevis) declined from 1995 to 2003 and was one of the rarer species. In terms relative abundance (kg per fisher per trip), P. laevis was the rarest of all species recorded.

In Pohnpei (Micronesia), P. laevis constituted 0.1% of serranid catch over a 5-month period in 2006 that included line and spear catch (Rhodes and Tupper 2007).

Fisheries-independent data
Despite extensive surveys in the Seychelles, P. laevis was only recorded on granitic reefs of the Mahe Plateau and then at very low densities. It was also the rarest species in a demographic study of Aldabra serranids (Grandcourt 2005).

(Pears 2005) (expressed as number of individuals (+/-SD) per 1000 sq. m)

West Indian Ocean
Seychelles granitic reefs 0.1 (0.1)
Northern Amirantes 0 (0)
Southern Amirantes 0 (0)

(Ayling Choat unpublished) (expressed as number of individuals (+/-SD) per 1000 sq. m)

Northern GBR
Fished reefs (1994/95): 0.3 (0.1)
Fished reefs (2001): 0.12 (0.08)
Unfished reefs (2001) 0.32 (0.09)

The summary of a comprehensive analysis of the distribution and abundance of four species of Plectropomus of the NE coast of Australia and the Coral Sea (Ayling and Ayling 1986) is provided below. All abundances are adjusted to numbers per 1000 sq. m

Geographic region.
Far North
Reef position Inner shelf 0 (0)
Mid shelf 0.09 (0.04)
Outer shelf 0.9 (0.1)
North
Inner shelf 0.01 (0.01)
Mid shelf 0.01 (0.02)
Outer shelf 0.4 (0.07)

South
Inner shelf 0 (0)
Mid shelf 0.1 (0.02)
Outer shelf 0.3 (0.06)

Coral Sea
Herald Cays 0.5 (0.7)
Lihou 1 0.6 (0.5)
Lihou 2 0.7 (0.8)
Lihou 3 0.6 (0.8)

Surveys on West Australian off-shore reefs (Done 1994) showed that P. laevis was never abundant compared to P. leopardus and P. areolatus. P. laevis was present mainly on outer reef slopes. Surveys at Ashmore Reef (Indian Ocean) (Kospartov et al. 2005) revealed very low numbers: 0.1 (1998) and 0.03 (2005) individuals per 1000 sq. m. The reduction in numbers may be due to heavy fishing on this reef by Indonesian fishers. No P. laevis were observed during comprehensive surveys of Cocos/Keeling and Christmas Island in 2004 (Choat unpublished).

Estimates of abundance (as individuals per 1000 sq. m) from outer reef habitats from three Pacific localities found the following: Fiji (0.54 individuals), New Caledonia (1.2 individuals), and Tonga (0.43 individuals). These numbers are consistent with estimates from other localities surveyed (IRD database).

No spawning aggregations sites for P. laevis have been identified in either Australia or the SW Pacific (Heemstra and Randall 1993).
Population Trend: Decreasing

Habitat and Ecology [top]

Habitat and Ecology: General
Plectropomus laevis is conspicuous on outer coral reef slopes throughout the Indo-Pacific, occurring in depths between 4 and 90 m (Heemstra and Randall 1993). P. laevis appears to be a relatively fast-growing species and reaches 50 cm in less than four years; females achieve maturity in under three years (Davies et al. 2006). Similar growth rates are recorded from individuals taken from the Western Indian Ocean (Grandcourt 2005). Fished populations of this species on the Great Barrier Reef have an age structure skewed strongly toward young (3 to 4 year old) fish and a high total mortality rate.

Plectropomus laevis feeds mostly on fishes and occasionally on crustaceans (Lieske and Myers 1994). The prey comprises a variety of large reef fishes, including groupers that is likely responsible for the high concentrations of ciguatera toxins (Randall 1980).

P. laevis attains 100 cm SL (about 125 cm TL) and a weight of 18 kg (Heemstra and Randall 1993).

Sexual pattern
Based on histological examination of gonads, P. laevis was suggested to be a monandric protogynous hermaphrodite, with males derived exclusively through sexual transition of mature females (Adams 2002, 2003). Adams (2002, 2003) found that male maturation was seen in transitional phase gonads only and that immature bisexuals were present.

Spawning
Komodo National Park: October to January (The Nature Conservancy, undated)

Colouration
This species occurs in two distinct color phases: the blacksaddled or barred, and the blue spot phase. The barred color phase is generally associated with smaller individuals although it is still retained in a minority of very large fish. In a comprehensive survey of the Great Barrier Reef, Davies et al. (2006) stated that the barred color pattern was retained in individuals up to 12 years of age but that the majority of individuals displaying this phase where immature females. A minority of secondary males also retained the barred color phase. Ayling (pers comm.) has not observed the barred phase in Coral Sea reefs.

Age and Growth data
Great Barrier Reef: Linf 948 mm FL K 0.14 (n=346) (Davies et al. 2006)
Aldabra Linf 1015 mm FL K 0.19 (n=22) (Grandcourt 2005)

Reproduction
P.laevis is a monandric protogynous hermaphrodite with highly biased female sex ratios (Adams 2002), although males may have been underrepresented in the sample. No historical fishing data specific to P.laevis is available to judge past population structure. Although small bisexual individuals were identified, the spermatocytes never passed beyond the secondary stage and no evidence of ovarian degeneration was observed. It was inferred that the male developmental pathway was monandric, with males only derived through sex change of mature females. The youngest male found was 9 years of age with transitional individuals occurring at 8-9 years. Sexual maturity occurred at 2.2 yrs (50% females mature) and at ~400 mm FL. (Davies et al. 2006).

Average age at maturity is 10.1 yrs (generation time calculated following Pianka (1978), using the formula t2 =(a+b)/2, where a=age at maturation and b=longevity Here, a= 2.2 years and longevity=18 yrs. Generation time is commonly assumed to be equivalent to age at 1st maturity.

Spawns in small groups (Samoilys, M., pers. comm.) and reported to spawn in an aggregation in Papua New Guinea (Hamilton 2003).
Systems: Marine

Threats [top]

Major Threat(s): The major threat for Plectropomus laevis is collection for the aquarium trade. It may turn up in live fish trade, but this is not considered to threaten this species. However, given strong interest in the live food trade and that large species tend to be taken as juveniles for this trade because of the small sizes preferred in restaurants, there is potential for increased exploitation. Hamilton (2003) reports declining catches from an aggregation noted by fishers in the Solomons.

Conservation Actions [top]

Conservation Actions: This species occurs in protected areas in portions of its range.

In Indonesia, a preliminary recommendation for closed areas within Komodo National Park has been designed (The Nature Conservancy, unknown year).

To date conservation actions include size limits, total area closures to fishing and temporal sales bans. The current management plan on the Great Barrier Reef Marine Park (GBRMP) has set a minimum size limit of 500 mm FL for this species. Approximately 30% of the GBRMP now comprises areas closed to fishing. However the primary habitat of this species in eastern Australia (exposed reef fronts on the northern Great Barrier Reef and Coral Sea reef systems) have large areas of reef open to fishing. Increasing ease of access and navigation means that the protection by isolation component will be reduced in the near future. In Pohnpei (Micronesia), the species is prohibited for sale, along with other groupers, during March and April (Rhodes and Tupper 2007).

Bibliography [top]

Ayling, A.M. and Ayling, A.L. 1986. Coral trout survey, Great Barrier Reef. Unpublished report.

Davies, C.R., Williams, A.J., Mapstone, B.D., Benzie, J., van Herwerden, L., Choat, J.H., Adams, S., Murchie, C.D., Bean, K., Carlos, G., Tobin, A., and Ackerman, J. 2006. Stock structure and regional variation in population dynamics of the Red Throat Emperor and other target species of the Queensland Tropical Reef Line Fishery.

Done, T.J., Williams, D. McB., Speare, P.J., Turak, E.I., Davidson, J., Devantier, L.M., Newman, S.J. and Hutchings, J.B. 1994. Surveys of coral and fish communities at Scott Reefs and Rowley Shoals.

Froese, R. and Pauly, D. 2000. FishBase 2000: Concepts, design and data sources. Manila Available at: http://www.fishbase.org.

Grandcourt, E.M. 2002. Demographic characteristics of a selection of exploited reef fish from the Seychelles: preliminary study.

Hamilton, R. 2003. A report on the status of exploited reef fish aggregations in the Solomon Islands and Papua New Guinea- Choiseul, Ysabel, Bougainville and Manus Provinces.

International Marinelife Alliance. 2003. Whole and retail prices of live reef food fish in Hong Kong (Excel format).

IUCN. 2008. 2008 IUCN Red List of Threatened Species. Available at: http://www.iucnredlist.org. (Accessed: 5 October 2008).

Kospartov, M., Berger, M., Ceccarelli, D. and Richards, Z. 2006. An assessment of the distribution and abundance of seacucumbers,Trochus, giant clams, fish and invasive marine species at Ashmore Reef National Nature Reserve and Cartier Island Marine Reserve.

Lau, P.P.F.and Li, L.W.H. 2000. Identification Guide to Fishes in the Live Seafood Trade of the Asia-Pacific Region..

Leiske, E. and Myers, R. 2002. Collins pocket guide to coral reef fishes. Princeton University Press, Princeton, USA.

Myers, R. 2006. Indo-Pacific Groupers. Unpublished distributional database.

Pears, R.J. 2005. Comparative demography and assemblage structure of serranid fishes: implications for conservation and fisheries management..

Randall, J.E. 1980. A survey of ciguatera at Enewetak and Bikini, Marshall Islands, with notes on the systematics and food habits of ciguatoxic fishes.

Rhodes, K.L. and Tupper, M.H. 2007. A preliminary market-based survey of the Pohnpei, Micronesia, grouper (Serranidae: Epinehelinae) fishery reveals unsustainable fishing practices.

Sattar, S.A. and Adams, M.S. 2005. Review of the grouper fishery of the Maldives with additional notes on the Faafu Atoll fishery.

Scales, H., Balmford, A. and Manica, A. 2007. Impacts of the live reef fish trade on populations of coral reef fish off northern Borneo.

Sluka, R.D. 2002. Grouper and Napoleon wrasse ecology in Laamu Atoll, Republic of Maldives: part 3. Fishing effects and management of the live fish-food trade.

The Nature Conservancy. Fish monitoring in Komodo National Park.

Van Herwerden, L., Benzie, J., Peplow, L. and Davies, C. 2000. Microsatellite markers for coral trout (Plectropomus laevis) and red throat emperor (Lethrinus miniatus) and theit utility in other species of reef fish.

Van Herwerden, L., Davies, C.R. and Choat, J.H. 2002. Phylogenetic and evolutionary perspectives of the Indo-Pacific grouper Plectropomus species on the Great Barrier Reef, Australia (Brief Communication).

Citation: Choat, J.H., Liu, M., Craig, M.T., Yeeting, B. & Robinson, J. 2008. Plectropomus laevis. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 17 April 2014.
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